Desiccating apparatus



April 17, 1962 H. c. ROBBINS- DESICCATING APPARATUS 2 Sheets-Sheet 1Filed March 25, 1957 INVENTOR. uw/ 6f Pose/Ms w 1 1 4 9 2 9 /2 .02 1a WM2 2 MW 2 3 J n April 17, 1962 H. c. ROBBINS 3,929,581

' DESICCATING APPARATUS Filed March 25, 1957 2 Sheets-Sheet 2 INVENTOR.14 06 6? 2053/:

United States Patent DESICCATING APPARATKE 1 Hugh C. Robbins, LosAngeles, Calif., assignor to Robbins Aviation, The, Los Angeles, Calif.,a corporation of California Filed Mar. 25, 1957, Ser. No. 648,313 6Claims. (Cl. 55-316) This invention relates to desiccating apparatus,and particularly to apparatus that functions to dehydrate any gas or airwhich, of course, is actually a gas composed largely of nitrogen andoxygen.

In desiccating apparatus as now employed, it is the usual practice toprovide a series of desiccating cylinders containing desiccant throughwhich the gas to be dried is passed. It flows in at one end of thecylinder and out at the other. This way of passing the gas through thedesiccant may be more orless satisfactory when the gas is at relativelylow pressure, and when the output of dedydrated gas is not required tobe in large quantities.

. On of the objects of this invention is to provide an improveddehydrator or desiccator for removing moisture from a pressurized gas.

Another object is to provide a unit having features of construction thatfacilitate its being connected up into a bank of similar units throughwhich the gas passes in succession.

' Another object is to provide an organization of units and connectingpiping that will facilitate the use of an arrangement in which the unitscan be aligned with each other in an upright position, with their basesall resting upon a common support such as a floor or a shelf, and withall the pipe connectionsattached to the upper ends or heads of thecasings, preferably the heads of the units.

An arrangement such as just described makes it possible to desiccate agas from a bottle under high pressure, connected to the first unit ofthe series or set, and passing thereafter through a series of units. Inthis way a very effective desiccation can be arrived at by stages. Thismode of operation has commercial advantages in practice because it makesit possible, if desired, to draw off a gas being processed, that hasarrived at a certain degree of desiccation which may be sufficient tofulfill the purposes of a purchaser who does not require a high' degreeof desiccation in the gas he obtains.

t Further objects of the invention will become evident from a carefulreading of this specification and study of the accompanying drawing.

A preferred embodiment of the invention is described in the followingspecification, while the broad scope of the invention is pointed out inthe appended claims.

In the drawing:

FIGURE 1 is a side elevation of a unit desiccator, certain parts beingbroken away to show inner portions in section to facilitate thedisclosure of the invention.

FIGURE 2 is a side elevation of a bank of several of the unitdesiccators connected up for flow of the gas from left to rightthrough-the bank.

Referring more particularly to the parts, in practicing the invention Iprovide a pressure vessel in the nature of a cylindrical shell or barrel1,- the side wall of which is relatively thick, as shown, i.e., ofsufiicient thickness to withstand any internal gas pressure to which itmay be subjected.

This barrel has at one end a head 2 which is provided with an innerscrew threaded plug 2a screwed into the interiorly screw threaded end ofbarrel 1, as at 3. When tightened up on the thread connection 3, anannular shoulder 4 seats against the end face of the barrel 1 andcompresses an O-ring 5 held in opposing half round grooves in theabutting faces to afford a gas-tight joint.

When the gas to be desiccated arrives from a bottle and a communicatinginlet port 14 which may be formed by drilling in through the inner face15 of the head 2.

The drilled port 14 is also counterbored, as at 20, with a drill ofslightly larger diameter than the port 14, so as to form an annularshoulder 16, that operates as a seat, and stop, for the end face of anipple 17 carried by the end closure 18 of a replaceable desiccantcartridge 19.

Port 14 is co-axial in the cylindrical barrel 1, and the nipple fitstightly in the counterbore 20 when shoved into a seating positiontherein.

The end closure 18 is a solid irnperforate head with its edge crimpedinto 'a flange 21 tightly embracing the upper edge of a relatively thinside wall tube 22, annularly spaced inside barrel 1 to provide alater-mentioned gas return duct, and which is irnperforate excepting forlater-mentioned ports or perforations adjacent its end remote from theclosure 18. Inside this tube 22, between a pair of presently describedperforated end cups, is a body of suitable desiccant material 23.

In order to establish a tight leak-proof fit for the nipple 17, thecounterbore 20* is undercut to form a groove to receive an O-ring 24.

The nipple 17 delivers the gas into a delivery chamber 25 formed in cup26, the cylindrical side wall of which fits tight into the end of thecartridge tube 22.

The bottom wall of cup 26 has a multiplicity of perforations 28 thatdeliver the gas in spaced-streams through a wad or filter disc 29 ofpacking positioned adjacent the cup. This packing may be cut with a diefrom a glass-wool stock of approximately 2 inches in thickness andcompressed to a thickness of one-quarter of an inch up to three eighthsof an inch thickness.

As illustrated in FIGURE 1, a similar packing wad may also be used atabout the middle of the cartridge to separate two sections of a dryingagent or desiccant preferably composed of mobile bead silica gel(molecular sieve 4A-l3X). A final packing or filter disc 2? is placed atthe opposite end of the cartridge, as shown.

When the gas has percolated through the two sections of desiccant andthe three wads 29 including the one adjacent the far end of thecartridge 19, it flows into 'the chamber in far end cup 30 of thecartridge 19.

This cup 30 is somewhat similar to the first-mentioned cup 18, in format least, so ofcourse, the gas flows through its perforations 31 to'theinterior of the cup.

But in this cup 30 there are perforations 32 in its side wallregistering with others in the cartridge tube 22 through which the gaspasses into the annular return duct 33 between cartridge tube 22 and thepressure vessel barrel 1.

The cartridge is completed by an end closure 34, which may also haveperforations 35 but they are not essential if there is sulficienteflective total area in the perforations 32.

The pressure vessel is completed by an end plug 36 which is threaded, asat 37, into the end of barrel 1 remote from head 2. This plug 36 issealed to barrel 1 by the O-ring 38 carried in a groove 38a around itsinner end. So, no shoulder is necessary here; but the lower face of thisplug 36 is provided with spaced sockets 39 to take the spurs of aspanner wrench when securing it into place.

When the gases flowing up in the annular duct 33 arrive at the upper endthey pass into a receiving space 40 from which they pass up throughcommunicating drilled ducts 41 and 42 to reach an outlet elbow 43connecting to a pipe 44. Couplings 45 are provided for connecting theinlet elbow and the outlet elbow to their corresponding inlet and outletpipes that connect them to a series of cooperating units such as shownin FIG- URE 2.

In FIGURE 2, two desiccatiug units 46 and 45a are shown, one of which isshown in detail in FIGURE 1.

These units are connected together in series in tandem arrangement, downstream with respect to the direction of flow of the gas from a filter47, which is generally necessary to remove some impurities and somemoisture before the gas reaches the desiccators.

If desired, a Y-stub connection 48 may be inserted in the line 49between the two units 46 and 46a, flow through which is control-led byopening a valve with a hand wheel 50. As this connection leads on fromthe line at an angle, gas having the degree of desiccation accomplishedby the unit 46 can be drawn off if desired without interrupting theoperation of the equipment.

It Will be seen that I have provided a desiccant unit comprising aheavy, permanent pressure vessel, adapted to be made up in a system ofpiping connecting to other desiccant and/or filter units, and a lighterweight, replaceable desiccant cartridge positioned therewithin. As willbe clear from the drawings, access may be readily had to the interior ofthe pressure vessel for installation or replacement of cartridges byeither unscrewing barrel 1 from head 2, or removing end plug 36. Toinstall the desiccant cartridge, its nipple 17 is simply inserted incounterbore 20, and the cartridge shoved ahead until the end of thenipple has engaged the stop seat 16 in the counterbore. efiected atO-ring 24, preventing bypassing of the gas to the space 40. When thecartridge is so positioned by stop seat 16, the space 40 accommodatesgas flow from return duct 33 to outlet 41 in head 2.

Attention is particularly directed to the fact that gases introducedinto the pressure vessel are directed immediately, by way of nipple 17,into the interior of the cartridge and to the packing pads 29* anddesiccant material contained therewithin. Thus the incoming gases areexcluded from contact with interior surfaces of the chamber in thepressure vessel until after they have traversed the full length of thecartridge, and the packing and desiccant material contained therein. Theincoming gas is thus purified within the cartridge before it contactsany interior surfaces of the chamber in the pressure vessel. Afterpassage through the cartridge, the purified gas is discharged from thecartridge to the annular return duct 33, and at this point, it sweepsfor the first time over interior surfaces of the chamber in the pressurevessel as it flows along duct 33 to the space 40 between the cartridgeand head 2, and finally exits through the outlet in the head. Theinterior surfaces of the pressure vessel therefore remain clean and dry,eliminating the necessity for frequent cleaning otherwise required.

Many other embodiments of the invention may be resorted to withoutdeparting from the spirit of the invention.

I claim as my invention and desire to secure by Letters Patent:

1. A dessicator for pressurized gases, comprising: a pressure vesselembodying a relatively thick-walled barrel, a head joined gas-tight toone end of said barrel and alfording an interior face exposed to theinterior of said vessel, and a gas-tight closure for the other end ofsaid barrel; and a replaceable desiccant cartridge Within said barrel,said cartridge comprising a relatively thin exterior side wall tubeannularly spaced inside said pressure vessel barrel, whereby to affordan annular gas duct between the exterior side wall tube of saidcartridge and the inside of said pressure vessel barrel, an end closureA pressure seal is automatically exteriorly of the head and having aterminal portion opening through said interior face and extendingaxially of said barrel toward the adjacent cartridge end closure, anipple on said last-mentioned end closure projecting axially therefromand receivable and pressure sealed within said terminal portion of saidgas inlet passage in said head, and there being a gas outlet passage insaid head opening exteriorly of said head and having a terminal portionopening through said interior face of said head, all in such manner asto provide a gas flow path inwardly via said gas inlet passage, thencedirectly via said nipple to the interior of said cartridge at thecorresponding end thereof, thence through the desiccant material in saidcartridge to the ported opposite end of the latter, thence from saidported opposite end of said cartridge to said annular gas duct, andthence along said annular gas duct outside said cartridge to and throughsaid gas outlet passage in said head. 7

2. A desiccator for pressurized gases, comprising: a pressure vesselembodying a relatively thick-walled barrel, a head joined gas-tight toone end of said barrel and affording an interior face exposed to theinterior of said vessel, and a gas-tight closure for the other end ofsaid barrel; and a replaceable desiccant cartridge within said barrel,said cartridge comprising a relatively thin exterior side wall tubeannularly spaced inside said pressure vessel barrel, whereby to affordan annular gas duct between the exterior sidewall tube of said cartridgeand the inside of said pressure vessel barrel, an end closure for theend of said cartridge side wall tube nearest said pressure vessel head,said side wall tube being imperforate from its end nearest said pressurevessel head to a point near its opposite end, an end closure for theopposite end of said cartridge side wall tube, said cartridge beingported adjacent its said opposite end for gas flow to said annular gasduct, and a body of desiccant material within said cartridge; saidpressure vessel head having a gas inlet passage therethrough includingan inlet port opening exteriorly of the head and having a terminalportion opening through said interior face and extending axially of saidbarrel toward the adjacent cartridge end closure, a nipple on saidlast-mentioned end closure projecting axially therefrom and receivableand pressure sealed within said terminal portion of said gas inletpassage in said head, an outwardly facing seat within said terminalportion of said gas inlet passage, spaced inwardly of the exit openingthereof by a distance such as to limit movement of said cartridge towardsaid pressure vessel head to a position afiording a clearance space forgas passage from said annular duct to said gas outlet passage betweenthe adjacent end closure of the cartridge and said inner face of saidhead, and'there being a gas outlet passage in said head leading fromsaid interior face thereof externally of said head, all in such manneras to provide a gas flow path inwardly via said gas inlet passage,thence directly via said nipple to the interior of said cartridge at thecorresponding end thereof, thence through the desiccant material in saidcartridge to the ported opposite end of the latter, thence from saidported opposite end of said cartridge to said annular gas duct, andthence along said annular gas duct outside said cartridge to and throughsaid gas outlet passage in said head.

3. A desiccator for pressurized gases, comprising: a pressure vesselembodying a relatively thick-walled barrel, a head joined gas-tight toone end of said barrel and alfording an interior face exposed to theinterior of said vessel, and a gas-tight closure for the other end ofsaid barrel; and a replaceable desiccant cartridge within said barrel,said cartridge comprising a relatively thin exterior side wall tubeannularly spaced inside said pressure vessel barrel, whereby to alfordan annular gas duct between the exterior side wall tube of saidcartridge and the inside of said pressure vessel barrel, an end closurefor the end of said cartridge side wall tube nearest said pressurevessel head, said side wall tube being imperforate from its end nearestsaid pressure vessel head to a point near its opposite end, an endclosure for the opposite end of said cartridge side wall tube, saidcartridge being ported adjacent its said opposite end for gas flow tosaid annular gas duct, and a body of desiccant material within saidcartridge; said pressure vessel head having a gas inlet passagetherethrough including an inlet port opening exteriorly of the head andhaving a terminal portion opening through said interior face andextending axially of said barrel toward the adjacent cartridge endclosure, a nipple on said last-mentioned end closure projecting axiallytherefrom and receivable within said terminal portion of said gas inletpassage in said head, an O-ring seal seated in said terminal portion ofsaid gas inlet passage and which receives and forms a pressure seal tosaid cartridge nipple, said cartridge nipple in pressure sealedreception in said gas inlet passage constituting the sole securing meansbetween the cartridge and pressure vessel head whereby connectiontherebetween may be made by straight ahead movement of said cartridgetoward said head, and there being a gas outlet passage in said headleading from said interior face thereof externally of said head, all insuch manner as to provide a gas flow path inwardly via said gas inletpassage, thence directly via said nipple to the interior of saidcartridge at the corresponding end thereof, thence through the desiccantmaterial in said cartridge to the ported opposite end of the latter,thence from said ported opposite end of said cartridge to said annulargas duct, and thence along said annular gas duct outside said cartridgeto and through said gas outlet passage in said head.

4. The subject matter of claim 1, wherein said cartridge includesperforated walls extending transversely across said cartridge side walltube and spaced inwardly of the end closures thereof, so as to form airchambers at the ends of the cartridge, said perforated walls beingformed with a multiplicity of perforations distributed throughout thearea thereof, and said desiccant material being positioned between saidperforated walls.

5. The subject matter of claim 4, including also filter means positionedwithin and across said cartridge side wall tube between said perforatedwalls.

6. A' desiccator for pressurized gases, comprising: a pressure vesselcomprising a relatively thick-walled barrel, a head closing and pressuresealing one end thereof, and a closure closing and pressure sealing theopposite end thereof; and a replaceable desiccant cartridge within saidbarrel comprising a desiccant-filled, relatively thinwalled imperforatetube and end closures therefor annularly spaced inside said barrel,whereby to provide a gas duct therearound; a gas inlet passage in saidhead; a conduit communicating between said gas inlet passage and theinterior of said desiccant cartridge in the end region thereof nearestsaid pressure vessel head, said cartridge being ported for outlet ofdehydrated gases therefrom to said annular gas passage adjacent itsopposite end region, and there being a gas outlet passage in said headopening toward the opposite end of the barrel to the interior of thelatter and communicating via the adjacent end region of said barrel withsaid annular gas duct.

References Cited in the file of this patent UNITED STATES PATENTS1,872,783 Miller Aug. 23, 1932 2,181,672 Sutclifie et a1. Nov. 28, 19392,691,425 Daniels Oct. 12, 1954 2,698,061 Jaubert Dec. 28, 19542,758,719 Line Aug. 14, 1956

